California mines and minerals . hing it. The gold, black sand and all fines pass through the per-forations into a distributing box, whilst the coarse material travelsby gravity into an elevator, or stacker, which dumps it at the requiredheight above the surface of the water. This elevator is also of thecontinuous bucket type, the buckets being close connected and run-ning on rollers carried by two steel 1 beams. The gold and finespass through a number of adjustable doors on to the various sectionsof gold-saving tables. These tables are made of cast iron, thusobviating the cracking and shrinkin
California mines and minerals . hing it. The gold, black sand and all fines pass through the per-forations into a distributing box, whilst the coarse material travelsby gravity into an elevator, or stacker, which dumps it at the requiredheight above the surface of the water. This elevator is also of thecontinuous bucket type, the buckets being close connected and run-ning on rollers carried by two steel 1 beams. The gold and finespass through a number of adjustable doors on to the various sectionsof gold-saving tables. These tables are made of cast iron, thusobviating the cracking and shrinking which wood is subject to, andare covered with cocoa matting and expanded metal, the finest goldsaver yet discovered. Any one section can be cut out and washed upwithout interfering with the operation of the dredge. Nearly all thegold is caught within a very few inches of the head of the table,which is 8 feet long with an area of 200 square feet. The sand andwaste fines pass from the tables into a sluice fitted with angle-iron. 92 CALIFORNIA MINES AND MINERALS riffles, and are thus conveyed over-board astern of the dredge. Thissluice is more of a conveyer than a gold saver, as the tables practi-cally catch all the gold. During a period when $2, was taken off the tables, only$ was taken out of the sluices. The most careful panning willseldom yield a color in the tailings. The motive power to operate the dredges is in most cases compound condensing, vertical engine, indicating about 40 horse-power, running the whole dredge, except the electric light plant andwinch, which have separate engines. The power is transmitted tothe buckets by ropes and gearing, a friction clutch being placed onthe countershaft so that, instead of breaking anything, in the eventof the buckets running up against solid, hard bed-rock or other obstruc-tion, the clutch merely slips and continues to slip until the winch maneases the strain, when the bucket belt starts again. Steam is suppli
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Keywords: ., bo, bookcentury1800, bookdecade1890, bookidcaliforniaminesm00cali
